From bbf63be4f331358173da26b888a10583fcc92ec0 Mon Sep 17 00:00:00 2001 From: Jonghwa Lee Date: Wed, 21 Nov 2012 13:31:01 +0900 Subject: Thermal: exynos: Add sysfs node supporting exynos's emulation mode. This patch supports exynos's emulation mode with newly created sysfs node. Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit. Thermal emulation mode supports software debug for TMU's operation. User can set temperature manually with software code and TMU will read current temperature from user value not from sensor's value. This patch includes also documentary placed under Documentation/thermal/. Signed-off-by: Jonghwa Lee Signed-off-by: Zhang Rui --- Documentation/thermal/exynos_thermal_emulation | 53 ++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 Documentation/thermal/exynos_thermal_emulation (limited to 'Documentation') diff --git a/Documentation/thermal/exynos_thermal_emulation b/Documentation/thermal/exynos_thermal_emulation new file mode 100644 index 00000000000..b73bbfb697b --- /dev/null +++ b/Documentation/thermal/exynos_thermal_emulation @@ -0,0 +1,53 @@ +EXYNOS EMULATION MODE +======================== + +Copyright (C) 2012 Samsung Electronics + +Written by Jonghwa Lee + +Description +----------- + +Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit. +Thermal emulation mode supports software debug for TMU's operation. User can set temperature +manually with software code and TMU will read current temperature from user value not from +sensor's value. + +Enabling CONFIG_EXYNOS_THERMAL_EMUL option will make this support in available. +When it's enabled, sysfs node will be created under +/sys/bus/platform/devices/'exynos device name'/ with name of 'emulation'. + +The sysfs node, 'emulation', will contain value 0 for the initial state. When you input any +temperature you want to update to sysfs node, it automatically enable emulation mode and +current temperature will be changed into it. +(Exynos also supports user changable delay time which would be used to delay of + changing temperature. However, this node only uses same delay of real sensing time, 938us.) + +Exynos emulation mode requires synchronous of value changing and enabling. It means when you +want to update the any value of delay or next temperature, then you have to enable emulation +mode at the same time. (Or you have to keep the mode enabling.) If you don't, it fails to +change the value to updated one and just use last succeessful value repeatedly. That's why +this node gives users the right to change termerpature only. Just one interface makes it more +simply to use. + +Disabling emulation mode only requires writing value 0 to sysfs node. + + +TEMP 120 | + | + 100 | + | + 80 | + | +----------- + 60 | | | + | +-------------| | + 40 | | | | + | | | | + 20 | | | +---------- + | | | | | + 0 |______________|_____________|__________|__________|_________ + A A A A TIME + |<----->| |<----->| |<----->| | + | 938us | | | | | | +emulation : 0 50 | 70 | 20 | 0 +current temp : sensor 50 70 20 sensor -- cgit v1.2.3 From 8ab3e6a08a98f7ff18c6814065eb30ba2e000233 Mon Sep 17 00:00:00 2001 From: Eduardo Valentin Date: Wed, 2 Jan 2013 15:29:39 +0000 Subject: thermal: Use thermal zone device id in netlink messages This patch changes the function thermal_generate_netlink_event to receive a thermal zone device instead of a originator id. This way, the messages will always be bound to a thermal zone. Signed-off-by: Eduardo Valentin Reviewed-by: Durgadoss R Signed-off-by: Zhang Rui --- Documentation/thermal/sysfs-api.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt index 88c02334e35..526d4b90d6c 100644 --- a/Documentation/thermal/sysfs-api.txt +++ b/Documentation/thermal/sysfs-api.txt @@ -329,8 +329,9 @@ The framework includes a simple notification mechanism, in the form of a netlink event. Netlink socket initialization is done during the _init_ of the framework. Drivers which intend to use the notification mechanism just need to call thermal_generate_netlink_event() with two arguments viz -(originator, event). Typically the originator will be an integer assigned -to a thermal_zone_device when it registers itself with the framework. The +(originator, event). The originator is a pointer to struct thermal_zone_device +from where the event has been originated. An integer which represents the +thermal zone device will be used in the message to identify the zone. The event will be one of:{THERMAL_AUX0, THERMAL_AUX1, THERMAL_CRITICAL, THERMAL_DEV_FAULT}. Notification can be sent when the current temperature crosses any of the configured thresholds. -- cgit v1.2.3 From d6d71ee4a14ae602db343ec48c491851d7ec5267 Mon Sep 17 00:00:00 2001 From: Jacob Pan Date: Mon, 21 Jan 2013 04:37:57 -0800 Subject: PM: Introduce Intel PowerClamp Driver Intel PowerClamp driver performs synchronized idle injection across all online CPUs. The goal is to maintain a given package level C-state ratio. Compared to other throttling methods already exist in the kernel, such as ACPI PAD (taking CPUs offline) and clock modulation, this is often more efficient in terms of performance per watt. Please refer to Documentation/thermal/intel_powerclamp.txt for more details. Signed-off-by: Arjan van de Ven Signed-off-by: Jacob Pan Signed-off-by: Zhang Rui --- Documentation/thermal/intel_powerclamp.txt | 307 +++++++++++++++++++++++++++++ 1 file changed, 307 insertions(+) create mode 100644 Documentation/thermal/intel_powerclamp.txt (limited to 'Documentation') diff --git a/Documentation/thermal/intel_powerclamp.txt b/Documentation/thermal/intel_powerclamp.txt new file mode 100644 index 00000000000..332de4a39b5 --- /dev/null +++ b/Documentation/thermal/intel_powerclamp.txt @@ -0,0 +1,307 @@ + ======================= + INTEL POWERCLAMP DRIVER + ======================= +By: Arjan van de Ven + Jacob Pan + +Contents: + (*) Introduction + - Goals and Objectives + + (*) Theory of Operation + - Idle Injection + - Calibration + + (*) Performance Analysis + - Effectiveness and Limitations + - Power vs Performance + - Scalability + - Calibration + - Comparison with Alternative Techniques + + (*) Usage and Interfaces + - Generic Thermal Layer (sysfs) + - Kernel APIs (TBD) + +============ +INTRODUCTION +============ + +Consider the situation where a system’s power consumption must be +reduced at runtime, due to power budget, thermal constraint, or noise +level, and where active cooling is not preferred. Software managed +passive power reduction must be performed to prevent the hardware +actions that are designed for catastrophic scenarios. + +Currently, P-states, T-states (clock modulation), and CPU offlining +are used for CPU throttling. + +On Intel CPUs, C-states provide effective power reduction, but so far +they’re only used opportunistically, based on workload. With the +development of intel_powerclamp driver, the method of synchronizing +idle injection across all online CPU threads was introduced. The goal +is to achieve forced and controllable C-state residency. + +Test/Analysis has been made in the areas of power, performance, +scalability, and user experience. In many cases, clear advantage is +shown over taking the CPU offline or modulating the CPU clock. + + +=================== +THEORY OF OPERATION +=================== + +Idle Injection +-------------- + +On modern Intel processors (Nehalem or later), package level C-state +residency is available in MSRs, thus also available to the kernel. + +These MSRs are: + #define MSR_PKG_C2_RESIDENCY 0x60D + #define MSR_PKG_C3_RESIDENCY 0x3F8 + #define MSR_PKG_C6_RESIDENCY 0x3F9 + #define MSR_PKG_C7_RESIDENCY 0x3FA + +If the kernel can also inject idle time to the system, then a +closed-loop control system can be established that manages package +level C-state. The intel_powerclamp driver is conceived as such a +control system, where the target set point is a user-selected idle +ratio (based on power reduction), and the error is the difference +between the actual package level C-state residency ratio and the target idle +ratio. + +Injection is controlled by high priority kernel threads, spawned for +each online CPU. + +These kernel threads, with SCHED_FIFO class, are created to perform +clamping actions of controlled duty ratio and duration. Each per-CPU +thread synchronizes its idle time and duration, based on the rounding +of jiffies, so accumulated errors can be prevented to avoid a jittery +effect. Threads are also bound to the CPU such that they cannot be +migrated, unless the CPU is taken offline. In this case, threads +belong to the offlined CPUs will be terminated immediately. + +Running as SCHED_FIFO and relatively high priority, also allows such +scheme to work for both preemptable and non-preemptable kernels. +Alignment of idle time around jiffies ensures scalability for HZ +values. This effect can be better visualized using a Perf timechart. +The following diagram shows the behavior of kernel thread +kidle_inject/cpu. During idle injection, it runs monitor/mwait idle +for a given "duration", then relinquishes the CPU to other tasks, +until the next time interval. + +The NOHZ schedule tick is disabled during idle time, but interrupts +are not masked. Tests show that the extra wakeups from scheduler tick +have a dramatic impact on the effectiveness of the powerclamp driver +on large scale systems (Westmere system with 80 processors). + +CPU0 + ____________ ____________ +kidle_inject/0 | sleep | mwait | sleep | + _________| |________| |_______ + duration +CPU1 + ____________ ____________ +kidle_inject/1 | sleep | mwait | sleep | + _________| |________| |_______ + ^ + | + | + roundup(jiffies, interval) + +Only one CPU is allowed to collect statistics and update global +control parameters. This CPU is referred to as the controlling CPU in +this document. The controlling CPU is elected at runtime, with a +policy that favors BSP, taking into account the possibility of a CPU +hot-plug. + +In terms of dynamics of the idle control system, package level idle +time is considered largely as a non-causal system where its behavior +cannot be based on the past or current input. Therefore, the +intel_powerclamp driver attempts to enforce the desired idle time +instantly as given input (target idle ratio). After injection, +powerclamp moniors the actual idle for a given time window and adjust +the next injection accordingly to avoid over/under correction. + +When used in a causal control system, such as a temperature control, +it is up to the user of this driver to implement algorithms where +past samples and outputs are included in the feedback. For example, a +PID-based thermal controller can use the powerclamp driver to +maintain a desired target temperature, based on integral and +derivative gains of the past samples. + + + +Calibration +----------- +During scalability testing, it is observed that synchronized actions +among CPUs become challenging as the number of cores grows. This is +also true for the ability of a system to enter package level C-states. + +To make sure the intel_powerclamp driver scales well, online +calibration is implemented. The goals for doing such a calibration +are: + +a) determine the effective range of idle injection ratio +b) determine the amount of compensation needed at each target ratio + +Compensation to each target ratio consists of two parts: + + a) steady state error compensation + This is to offset the error occurring when the system can + enter idle without extra wakeups (such as external interrupts). + + b) dynamic error compensation + When an excessive amount of wakeups occurs during idle, an + additional idle ratio can be added to quiet interrupts, by + slowing down CPU activities. + +A debugfs file is provided for the user to examine compensation +progress and results, such as on a Westmere system. +[jacob@nex01 ~]$ cat +/sys/kernel/debug/intel_powerclamp/powerclamp_calib +controlling cpu: 0 +pct confidence steady dynamic (compensation) +0 0 0 0 +1 1 0 0 +2 1 1 0 +3 3 1 0 +4 3 1 0 +5 3 1 0 +6 3 1 0 +7 3 1 0 +8 3 1 0 +... +30 3 2 0 +31 3 2 0 +32 3 1 0 +33 3 2 0 +34 3 1 0 +35 3 2 0 +36 3 1 0 +37 3 2 0 +38 3 1 0 +39 3 2 0 +40 3 3 0 +41 3 1 0 +42 3 2 0 +43 3 1 0 +44 3 1 0 +45 3 2 0 +46 3 3 0 +47 3 0 0 +48 3 2 0 +49 3 3 0 + +Calibration occurs during runtime. No offline method is available. +Steady state compensation is used only when confidence levels of all +adjacent ratios have reached satisfactory level. A confidence level +is accumulated based on clean data collected at runtime. Data +collected during a period without extra interrupts is considered +clean. + +To compensate for excessive amounts of wakeup during idle, additional +idle time is injected when such a condition is detected. Currently, +we have a simple algorithm to double the injection ratio. A possible +enhancement might be to throttle the offending IRQ, such as delaying +EOI for level triggered interrupts. But it is a challenge to be +non-intrusive to the scheduler or the IRQ core code. + + +CPU Online/Offline +------------------ +Per-CPU kernel threads are started/stopped upon receiving +notifications of CPU hotplug activities. The intel_powerclamp driver +keeps track of clamping kernel threads, even after they are migrated +to other CPUs, after a CPU offline event. + + +===================== +Performance Analysis +===================== +This section describes the general performance data collected on +multiple systems, including Westmere (80P) and Ivy Bridge (4P, 8P). + +Effectiveness and Limitations +----------------------------- +The maximum range that idle injection is allowed is capped at 50 +percent. As mentioned earlier, since interrupts are allowed during +forced idle time, excessive interrupts could result in less +effectiveness. The extreme case would be doing a ping -f to generated +flooded network interrupts without much CPU acknowledgement. In this +case, little can be done from the idle injection threads. In most +normal cases, such as scp a large file, applications can be throttled +by the powerclamp driver, since slowing down the CPU also slows down +network protocol processing, which in turn reduces interrupts. + +When control parameters change at runtime by the controlling CPU, it +may take an additional period for the rest of the CPUs to catch up +with the changes. During this time, idle injection is out of sync, +thus not able to enter package C- states at the expected ratio. But +this effect is minor, in that in most cases change to the target +ratio is updated much less frequently than the idle injection +frequency. + +Scalability +----------- +Tests also show a minor, but measurable, difference between the 4P/8P +Ivy Bridge system and the 80P Westmere server under 50% idle ratio. +More compensation is needed on Westmere for the same amount of +target idle ratio. The compensation also increases as the idle ratio +gets larger. The above reason constitutes the need for the +calibration code. + +On the IVB 8P system, compared to an offline CPU, powerclamp can +achieve up to 40% better performance per watt. (measured by a spin +counter summed over per CPU counting threads spawned for all running +CPUs). + +==================== +Usage and Interfaces +==================== +The powerclamp driver is registered to the generic thermal layer as a +cooling device. Currently, it’s not bound to any thermal zones. + +jacob@chromoly:/sys/class/thermal/cooling_device14$ grep . * +cur_state:0 +max_state:50 +type:intel_powerclamp + +Example usage: +- To inject 25% idle time +$ sudo sh -c "echo 25 > /sys/class/thermal/cooling_device80/cur_state +" + +If the system is not busy and has more than 25% idle time already, +then the powerclamp driver will not start idle injection. Using Top +will not show idle injection kernel threads. + +If the system is busy (spin test below) and has less than 25% natural +idle time, powerclamp kernel threads will do idle injection, which +appear running to the scheduler. But the overall system idle is still +reflected. In this example, 24.1% idle is shown. This helps the +system admin or user determine the cause of slowdown, when a +powerclamp driver is in action. + + +Tasks: 197 total, 1 running, 196 sleeping, 0 stopped, 0 zombie +Cpu(s): 71.2%us, 4.7%sy, 0.0%ni, 24.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st +Mem: 3943228k total, 1689632k used, 2253596k free, 74960k buffers +Swap: 4087804k total, 0k used, 4087804k free, 945336k cached + + PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND + 3352 jacob 20 0 262m 644 428 S 286 0.0 0:17.16 spin + 3341 root -51 0 0 0 0 D 25 0.0 0:01.62 kidle_inject/0 + 3344 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/3 + 3342 root -51 0 0 0 0 D 25 0.0 0:01.61 kidle_inject/1 + 3343 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/2 + 2935 jacob 20 0 696m 125m 35m S 5 3.3 0:31.11 firefox + 1546 root 20 0 158m 20m 6640 S 3 0.5 0:26.97 Xorg + 2100 jacob 20 0 1223m 88m 30m S 3 2.3 0:23.68 compiz + +Tests have shown that by using the powerclamp driver as a cooling +device, a PID based userspace thermal controller can manage to +control CPU temperature effectively, when no other thermal influence +is added. For example, a UltraBook user can compile the kernel under +certain temperature (below most active trip points). -- cgit v1.2.3 From e6e238c38bd4d42d5e2cddb2165e1a46e0fb1200 Mon Sep 17 00:00:00 2001 From: Amit Daniel Kachhap Date: Mon, 4 Feb 2013 00:30:15 +0000 Subject: thermal: sysfs: Add a new sysfs node emul_temp for thermal emulation This patch adds support to set the emulated temperature method in thermal zone (sensor). After setting this feature thermal zone may report this temperature and not the actual temperature. The emulation implementation may be based on sensor capability through platform specific handler or pure software emulation if no platform handler defined. This is useful in debugging different temperature threshold and its associated cooling action. Critical threshold's cannot be emulated. Writing 0 on this node should disable emulation. Signed-off-by: Amit Daniel Kachhap Acked-by: Kukjin Kim Signed-off-by: Zhang Rui --- Documentation/thermal/sysfs-api.txt | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'Documentation') diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt index 526d4b90d6c..6859661c9d3 100644 --- a/Documentation/thermal/sysfs-api.txt +++ b/Documentation/thermal/sysfs-api.txt @@ -55,6 +55,8 @@ temperature) and throttle appropriate devices. .get_trip_type: get the type of certain trip point. .get_trip_temp: get the temperature above which the certain trip point will be fired. + .set_emul_temp: set the emulation temperature which helps in debugging + different threshold temperature points. 1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz) @@ -153,6 +155,7 @@ Thermal zone device sys I/F, created once it's registered: |---trip_point_[0-*]_temp: Trip point temperature |---trip_point_[0-*]_type: Trip point type |---trip_point_[0-*]_hyst: Hysteresis value for this trip point + |---emul_temp: Emulated temperature set node Thermal cooling device sys I/F, created once it's registered: /sys/class/thermal/cooling_device[0-*]: @@ -252,6 +255,16 @@ passive Valid values: 0 (disabled) or greater than 1000 RW, Optional +emul_temp + Interface to set the emulated temperature method in thermal zone + (sensor). After setting this temperature, the thermal zone may pass + this temperature to platform emulation function if registered or + cache it locally. This is useful in debugging different temperature + threshold and its associated cooling action. This is write only node + and writing 0 on this node should disable emulation. + Unit: millidegree Celsius + WO, Optional + ***************************** * Cooling device attributes * ***************************** -- cgit v1.2.3 From 76cc1887496fe80138c6b07c37d7f81e4cf27cde Mon Sep 17 00:00:00 2001 From: Kuninori Morimoto Date: Thu, 31 Jan 2013 09:05:26 +0000 Subject: thermal: rcar: add Device Tree support Support for loading the Renesas R-Car thermal module via devicetree. Signed-off-by: Kuninori Morimoto Signed-off-by: Zhang Rui --- .../devicetree/bindings/thermal/rcar-thermal.txt | 29 ++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/rcar-thermal.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/thermal/rcar-thermal.txt b/Documentation/devicetree/bindings/thermal/rcar-thermal.txt new file mode 100644 index 00000000000..28ef498a66e --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/rcar-thermal.txt @@ -0,0 +1,29 @@ +* Renesas R-Car Thermal + +Required properties: +- compatible : "renesas,rcar-thermal" +- reg : Address range of the thermal registers. + The 1st reg will be recognized as common register + if it has "interrupts". + +Option properties: + +- interrupts : use interrupt + +Example (non interrupt support): + +thermal@e61f0100 { + compatible = "renesas,rcar-thermal"; + reg = <0xe61f0100 0x38>; +}; + +Example (interrupt support): + +thermal@e61f0000 { + compatible = "renesas,rcar-thermal"; + reg = <0xe61f0000 0x14 + 0xe61f0100 0x38 + 0xe61f0200 0x38 + 0xe61f0300 0x38>; + interrupts = <0 69 4>; +}; -- cgit v1.2.3 From 7060aa36645c51d1205ef0e0cbf7b564f1f52f36 Mon Sep 17 00:00:00 2001 From: Nobuhiro Iwamatsu Date: Wed, 6 Feb 2013 06:35:24 +0000 Subject: thermal: Add support for the thermal sensor on Kirkwood SoCs This patch adds support for Kirkwood 88F6282 and 88F6283 thermal sensor. Signed-off-by: Nobuhiro Iwamatsu Signed-off-by: Andrew Lunn Signed-off-by: Zhang Rui --- .../devicetree/bindings/thermal/kirkwood-thermal.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/kirkwood-thermal.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/thermal/kirkwood-thermal.txt b/Documentation/devicetree/bindings/thermal/kirkwood-thermal.txt new file mode 100644 index 00000000000..8c0f5eb86da --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/kirkwood-thermal.txt @@ -0,0 +1,15 @@ +* Kirkwood Thermal + +This version is for Kirkwood 88F8262 & 88F6283 SoCs. Other kirkwoods +don't contain a thermal sensor. + +Required properties: +- compatible : "marvell,kirkwood-thermal" +- reg : Address range of the thermal registers + +Example: + + thermal@10078 { + compatible = "marvell,kirkwood-thermal"; + reg = <0x10078 0x4>; + }; -- cgit v1.2.3 From 74ffa64c23616706381c30064a47888382bba30f Mon Sep 17 00:00:00 2001 From: Andrew Lunn Date: Wed, 6 Feb 2013 06:35:26 +0000 Subject: Thermal: Dove: Add Themal sensor support for Dove. The Marvell Dove SoC has a thermal sensor. Add a driver using the thermal framework. Signed-off-by: Andrew Lunn Signed-off-by: Sebastian Hesselbarth Signed-off-by: Zhang Rui --- .../devicetree/bindings/thermal/dove-thermal.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/dove-thermal.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/thermal/dove-thermal.txt b/Documentation/devicetree/bindings/thermal/dove-thermal.txt new file mode 100644 index 00000000000..6f474677d47 --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/dove-thermal.txt @@ -0,0 +1,18 @@ +* Dove Thermal + +This driver is for Dove SoCs which contain a thermal sensor. + +Required properties: +- compatible : "marvell,dove-thermal" +- reg : Address range of the thermal registers + +The reg properties should contain two ranges. The first is for the +three Thermal Manager registers, while the second range contains the +Thermal Diode Control Registers. + +Example: + + thermal@10078 { + compatible = "marvell,dove-thermal"; + reg = <0xd001c 0x0c>, <0xd005c 0x08>; + }; -- cgit v1.2.3